1. Field of the Invention
The present invention relates to a film type antenna and, more particularly, to a film type antenna integrated with a mobile communication terminal case, and a mobile communication terminal case using the same.
2. Description of the Related Art
As mobile communication terminals such as GPS, PDAs, cellular phones, wireless notebook computers and the like have been widely popularized, there have been increasing demands for miniaturization. In order to meet such needs for miniaturization, the main focus has been maintaining diverse functions while reducing the volume of the mobile communication terminals. This has been especially the case for the antenna which is an essential component of a mobile communication terminal.
In general, among the antennas of the mobile communication terminals, external type antennas such as a rod antenna and a helical antenna are protruded in a predetermined length out of the terminal, hindering miniaturization and portability of the terminal. In addition, when the mobile communication terminal is dropped, this type of antenna is more likely to be destructed.
On the contrary, built-in antennas mounted inside mobile communication terminals have reduced risk of destruction, but miniaturization can also be a problem due to their physical size.
Recently, methods of forming the radiator of the antenna directly in a terminal case or an antenna base have been employed to promote maximal utilization of space.
FIG. 1(a) is a perspective view illustrating a conventional internal type antenna for a mobile communication terminal, and FIG. 1(b) is a schematic sectional view illustrating the internal type antenna mounted inside the mobile communication terminal.
Referring to FIG. 1(a), a base 11 made of a plastic material for internal type antennas and a radiator 13 of a patterned metal plate are fabricated, respectively, via injection and pressing, and then integrated together by fusion bonding.
However, this method limits miniaturization as the antenna requires a space to be mounted inside the mobile communication terminal.
The radiator 13 can be formed on the base 11 via printing conductive ink. However, as the antenna base is made of a plastic material, the procedure should be implemented at a temperature that does not cause deformation of the plastic material. Therefore, the antenna pattern should be printed using a low-temperature paste, thus limiting selection of the material because the paste should be selected in consideration of printability, adhesive property, etc.
In addition, to enhance the printability and adhesive quality of the conductive ink, the conductive ink contains conductive material as well as organic substances. Thus, when the conductive ink is treated at a high temperature, the organic substances are eliminated but when treated at a low temperature, the organic substances remain in the ink. The base of the antenna is made of a polymer-based material, hindering high temperature treatment, and as a result, the organic substances contained in the conductive ink remain even after the antenna radiator is formed. This results in low electric conductivity of the antenna radiator, problematically degrading the radiation characteristics of the antenna.
Furthermore, such an antenna pattern can easily be recognized by naked eyes or can easily be appropriated by a competitor via laser irradiation.